161817518587 has 4 divisors (see below), whose sum is σ = 161818887736. Its totient is φ = 161816149440.

The previous prime is 161817518573. The next prime is 161817518623. The reversal of 161817518587 is 785815718161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 785815718161 = 37 ⋅21238262653.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161817518587 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161817518887) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 488589 + ... + 749902.

It is an arithmetic number, because the mean of its divisors is an integer number (40454721934).

Almost surely, 2^161817518587 is an apocalyptic number.

161817518587 is a deficient number, since it is larger than the sum of its proper divisors (1369149).

161817518587 is a wasteful number, since it uses less digits than its factorization.

161817518587 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1369148.

The product of its digits is 3763200, while the sum is 58.

The spelling of 161817518587 in words is "one hundred sixty-one billion, eight hundred seventeen million, five hundred eighteen thousand, five hundred eighty-seven".